31 lines
3.8 KiB
HTML
31 lines
3.8 KiB
HTML
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Writing Attribute</title><meta name="generator" content="DocBook XSL Stylesheets V1.61.2"><link rel="home" href="index.html" title="Libxml Tutorial"><link rel="up" href="index.html" title="Libxml Tutorial"><link rel="previous" href="ar01s06.html" title="Writing element content"><link rel="next" href="ar01s08.html" title="Retrieving Attributes"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Writing Attribute</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="xmltutorialwritingattribute"></a>Writing Attribute</h2></div></div><div></div></div><p><a class="indexterm" name="id2587093"></a>
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Writing an attribute is similar to writing text to a new element. In
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this case, we'll add a reference <span class="acronym">URI</span> to our
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document. Full code:<a href="apf.html" title="F. Code for Add Attribute Example">Appendix F, <i>Code for Add Attribute Example</i></a>.</p><p>
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A <tt class="sgmltag-element">reference</tt> is a child of the <tt class="sgmltag-element">story</tt>
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element, so finding the place to put our new element and attribute is
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simple. As soon as we do the error-checking test in our
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<tt class="function">parseDoc</tt>, we are in the right spot to add our
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element. But before we do that, we need to make a declaration using a
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data type we have not seen yet:
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</p><pre class="programlisting">
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xmlAttrPtr newattr;
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</pre><p>
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We also need an extra xmlNodePtr:
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</p><pre class="programlisting">
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xmlNodePtr newnode;
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</pre><p>
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</p><p>
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The rest of <tt class="function">parseDoc</tt> is the same as before until we
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check to see if our root element is <tt class="sgmltag-element">story</tt>. If it is,
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then we know we are at the right spot to add our element:
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</p><pre class="programlisting">
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<a name="addreferencenode"></a><img src="images/callouts/1.png" alt="1" border="0"> newnode = xmlNewTextChild (cur, NULL, "reference", NULL);
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<a name="addattributenode"></a><img src="images/callouts/2.png" alt="2" border="0"> newattr = xmlNewProp (newnode, "uri", uri);
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</pre><p>
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</p><div class="calloutlist"><table border="0" summary="Callout list"><tr><td width="5%" valign="top" align="left"><a href="#addreferencenode"><img src="images/callouts/1.png" alt="1" border="0"></a> </td><td valign="top" align="left"><p>First we add a new node at the location of the current node
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pointer, <tt class="varname">cur.</tt> using the <a href="https://gnome.pages.gitlab.gnome.org/libxml2/devhelp/libxml2-tree.html#XMLNEWTEXTCHILD" target="_top">xmlNewTextChild</a> function.</p></td></tr></table></div><p>
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</p><p>Once the node is added, the file is written to disk just as in the
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previous example in which we added an element with text content.</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ar01s06.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="index.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ar01s08.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Writing element content </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Retrieving Attributes</td></tr></table></div></body></html>
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